package es.udc.cameraar2;

import android.content.Context;
import android.content.pm.PackageManager;
import android.hardware.Camera;


public class CameraFunctions {

	/** Check if this device has a camera */
	public static boolean checkCameraHardware(Context context) {
	    if (context.getPackageManager().hasSystemFeature(PackageManager.FEATURE_CAMERA)){
	        // this device has a camera
	        return true;
	    } else {
	        // no camera on this device
	        return false;
	    }
	}
	
	// decode Y, U, and V values on the YUV 420 buffer described as YCbCr_422_SP by Android 
	// David Manpearl 081201 
	public static void decodeYUV(int[] out, byte[] fg, int width, int height)
	        throws NullPointerException, IllegalArgumentException {
	    int sz = width * height;
	    if (out == null)
	        throw new NullPointerException("buffer out is null");
	    if (out.length < sz)
	        throw new IllegalArgumentException("buffer out size " + out.length
	                + " < minimum " + sz);
	    if (fg == null)
	        throw new NullPointerException("buffer 'fg' is null");
	    if (fg.length < sz)
	        throw new IllegalArgumentException("buffer fg size " + fg.length
	                + " < minimum " + sz * 3 / 2);
	    int i, j;
	    int Y, Cr = 0, Cb = 0;
	    
	    //Recorremos las filas
	    for (j = 0; j < height; j++) {
	    	
	        int pixPtr = j * width;
	        final int jDiv2 = j >> 1;
	    
	    	//Recorremos las columnas
	        for (i = 0; i < width; i++) {
	        	
	            Y = fg[pixPtr];
	            if (Y < 0)
	                Y += 255;
	            if ((i & 0x1) != 1) {
	                final int cOff = sz + jDiv2 * width + (i >> 1) * 2;
	                Cb = fg[cOff];
	                if (Cb < 0)
	                    Cb += 127;
	                else
	                    Cb -= 128;
	                Cr = fg[cOff + 1];
	                if (Cr < 0)
	                    Cr += 127;
	                else
	                    Cr -= 128;
	            }
	            int R = Y + Cr + (Cr >> 2) + (Cr >> 3) + (Cr >> 5);
	            if (R < 0)
	                R = 0;
	            else if (R > 255)
	                R = 255;
	            int G = Y - (Cb >> 2) + (Cb >> 4) + (Cb >> 5) - (Cr >> 1)
	                    + (Cr >> 3) + (Cr >> 4) + (Cr >> 5);
	            if (G < 0)
	                G = 0;
	            else if (G > 255)
	                G = 255;
	            int B = Y + Cb + (Cb >> 1) + (Cb >> 2) + (Cb >> 6);
	            if (B < 0)
	                B = 0;
	            else if (B > 255)
	                B = 255;
	            out[pixPtr++] = 0xff000000 + (B << 16) + (G << 8) + R;
	        }
	    }

	}
	
	
	
	
	/** A safe way to get an instance of the Camera object. */
	public static Camera getCameraInstance(){
	    Camera c = null;
	    try {
	        c = Camera.open(); // attempt to get a Camera instance
	    }
	    catch (Exception e){
	        // Camera is not available (in use or does not exist)
	    }
	    return c; // returns null if camera is unavailable
	}
	
	/** A safe way to get an instance of the Camera object. */
	public static Camera getCameraInstance(int i){
	    Camera c = null;
	    try {
	        c = Camera.open(i); // attempt to get a Camera instance
	    }
	    catch (Exception e){
	        // Camera is not available (in use or does not exist)
	    }
	    return c; // returns null if camera is unavailable
	}
	
	
	
	public static int getNumberOfCameras(){
		 return Camera.getNumberOfCameras();
	}
	
	
}
